A profile roller set with a roll-forming tool is known, for example, from the subject of DE 10 2010 053 547 A1, which was filed by the same applicant. The roll-forming tool described therein is developed further within the context of the present invention.
All information contained in said publication DE 10 2010 053 547 A1 is to be fully incorporated by reference in the present application as is fully set forth herein.
Furthermore, the same subject is known from DE 10 2013 006 216 A1, which also originated from the same applicant. Its information content is to be fully incorporated by reference herein in the description of the present invention as well.
An object (component) produced with a roll-forming tool according to DE 10 2013 006 216 A1 or DE 10 2010 053 547 A1 is described, for example, in DE 10 2013 006 150 A1. This publication also describes the roll-forming process in detail and accordingly, this invention description is to be fully incorporated by reference herein in the description of the present invention as well.
A description of a profile roller set according to the invention can therefore be found in one or more of the above publications.
Such a profile roller set is characterized in that a multitude of cassettes is equidistantly arranged over the outer circumference of a roll-forming tool, having profile rollers in their interior spaces, which roll out with their outer circumference the outer periphery of a component to be formed and therefore impart toothing to the component to be formed.
The manufacture of such rotationally symmetrical components aims, for example, at the production of a disk carrier for a double clutch system as described in DE 10 2013 216 747 A1.
However, the disadvantage of such a disk carrier is that its toothing geometry is shaped in the manner of corrugated sheet metal, meaning that the teeth have a small radius, but are equidistantly arranged over the outer circumference in a wave-like manner, which results in a profile as described, for example, in DE 10 2013 216 747 A1.
The application of such a disk carrier for a double clutch is the subject of, for example, DE 10 2014 211 633 A1 or DE 10 2012 213 119 B3.
The disadvantage of such disk carriers according to the prior art is their low engine-speed strength. This means that the part stretches at high speeds and that the wave-like toothing tends to level in the direction of the centrifugal force effect, which can damage the disk carrier.
The described disk carriers therefore only have low engine-speed strength. Such disk carriers can be operated at maximum speeds ranging from, e.g., 10,000 to 14,000 revolutions per minute. This defines the speed limitation of the disk carriers known from the prior art. The specified range is only a preferred embodiment. Higher speed ranges can be achieved.
Disk carriers designed in such a way that a narrow, peripheral, self-contained and unformed bridge remains between the inner diameter and the outer diameter of the toothing are known from multiple embodiments. The bridge is arranged in the toothing as an integrated hoop band cylinder, intended to increase the engine-speed strength of the disk carrier.
However, the prior art employs completely different methods of production, which are considered disadvantageous.
The unformed bridge of disk carriers is intended to achieve axial rigidity in the disk carrier to reduce flaring at high speeds.
The production of such disk carriers with the so-called hoop band used to employ an extruder mold for extruding the component. It is a cold rolling process, in which the component, consisting of a deformable sheet metal part, is generated by pressing it through an extruder mold. This requires bonderizing the component, meaning it has to be coated, which calls for an additional production process. Furthermore, the application of the known extrusion process cannot produce the same precision as the arrangement of the present invention.
Due to the anisotropy of the utilized sheet metal materials, asymmetries always occur during the extrusion process, which leads to undesirable and uncontrollable deformations that affect the accuracy of the disk carrier. The inaccuracies caused by the material's anisotropy do not occur during the extrusion process per se, but after removing the formed piece from the mold, as it springs back in an undesired manner that causes inaccuracies.
Furthermore, a method for the production of the disk carriers discussed herein by way of spin-forming rollers is known. However, this production process is very slow due to the technology of the utilized method.
In this method, a pre-formed piece is moved over a central, grooved mandrel and one or more profile rollers move around the pre-formed piece held on the mandrel. The roller pressure shapes the blank into the central original form.
There is also a single-groove rolling method, which works in such a way that the individual grooves of the workpiece are rolled out in sequence with a single tool, which is associated with a lengthy production time and also with inaccuracies that have to be accepted.
A further known method known as flat die rolling, in which the grooves of the workpiece are shaped with two opposite vertical toothing dies to create a profile in a longitudinal movement. This method is also associated with a long production time and inaccuracies that must be accepted.
A further known method is the hard stamping method, in which forming is achieved with forming rollers that hit the workpiece in the manner of hammers.
This method can only be used with a low production output.
Accordingly, the present invention is based on the task of optimizing a method and a tool to be used with the method for rolling disk carriers which are designed as a pot-shaped sheet metal part having inner and outer teeth in such a way that the resulting disk carriers show improved dimensional accuracy and a higher engine-speed strength.
In the prior art, it was necessary to reinforce the wall thickness of the disk carrier to increase engine-speed strength or to reinforce it with additional rigidity aids to achieve a high engine-speed strength.